<?php

class Persion {
    private $age = 22;
    
    public function getAge(){
        echo $this->age,'<br>';
    }
    public function __construct($age = 0)
    {
        $this->age = $age;
    }
}

class Stu extends Persion {
    private $age = 18;
    private $name = 'wangwu';
    public function __construct($name='zhaoliu',$age = 0)
    {
        parent::__construct($age);
        $this->name=$name;
    }
    public function intro(){
        parent::getAge();
    }
    public function getAge(){
        echo $this->age,'<br>';
    }
}


$lisi = new Stu('王五',16);
print_r($lisi);